A LED device creates a desired light emission pattern by harnessing light emitting diode (“LED”). In doing so, such devices typically blend light emanating from the LED's upper surface (i.e., “upper LED light”) with light emanating from the LED's side surface (i.e., “side LED light”).
The desired light emission pattern should not only be easily viewable—because LED devices are often incorporated in traffic signals, variable message signs, and various displays—but should also be efficiently created. That is, any LED light that is not effectively harnessed in a way that contributes to the desired light emission pattern represents wasted energy.
One prior art LED device involves placing a light reflecting cavity around the LED's side surface to reflect its “side LED light” upwards so that it blends with the “upper LED light” and effectively contributes to the desired light emission pattern. However, since the percentage of “upper LED light” to “side LED light” often varies from LED to LED, a light reflecting cavity that is not specifically tailored to an individual LED is often not fully effective in blending the “upper LED light” with the “side LED light”. Accordingly, such prior art devices are not fully effective in creating desired light emission patterns.
In order to address the blending limitations of light reflecting cavities, other prior art LED devices have employed a light reflecting encapsulant in conjunction with them. Such light reflecting encapsulants encapsulating the LED from the LED's base to the light reflecting encapsulant's outer surface, the latter extending significantly above the light reflecting cavity. Unfortunately, such LED devices waste a significant portion of LED light by reflecting it in undesired directions.
For example, as shown schematically in a prior art LED device 1 of FIG. 1, some of a LED's 2 light—such as light rays 5 and 7—is reflected “off track” before reaching (an example of) a desired light emission pattern 3. As is readily seen from this Figure, such light is wasted because a portion of a prior art light reflecting encapsulant 4 resides above a light reflecting cavity 8 (having a light reflecting mirror 9 on its surface). Accordingly, there is a need for a LED device and a method for directing LED light more effectively (towards a desired light emission pattern), and a method for constructing a LED device according to the present invention.